1. Field of the Invention
This invention relates to an apparatus and method for providing lateral support to cabinets during injection and curing of foam insulation, and more particularly to an apparatus and method for facilitating rapid changeover of support members between successive runs of differing cabinets.
2. Background of the Invention
Many types of cabinets, such as refrigerators and freezers, employ insulation surrounding the interior thereof to help maintain a desired internal temperature. Generally, such cabinets comprise a rear wall with depending side walls, wherein such walls have inner and outer surfaces with a small cavity therebetween. Insulating foam is injected into the cavity between the inner and outer surfaces of the rear and side walls. Due to the high foam injection pressures and expansion of the foam during curing, significant pressure is exerted on the interior and exterior walls of the cabinet. To resist undesirable bulging of the walls due to the pressure exerted thereon, shoring members are secured flush against the internal and external walls during the insulation process.
It is known to employ a collapsible core or plug for supporting the interior walls of cabinets whereby the core or plug is moved into and out of the interior of a cabinet to be insulated. After insertion of the core into the cabinet interior the core's plurality of shoring panels are extended to abut the cabinet interior to provide support thereto during curing. The core is collapsed, with the shoring panels retracted away from the interior walls of the cabinet, during insertion and removal of the core from the cabinet interior so as to prevent damage the cabinet interior thereupon.
It is also known to provide a mechanism for storing a plurality of different cores and means for automatically manipulating the different cores into an operative position for insertion within the cabinet interior. For instance, in DeRossi U.S. Pat. No. 4,664,614 a plurality of cores are carried on a common rotatable drum whereby the core desired for a given application is selectively rotated into position. Thereafter, the cabinets are raised and lowered into the foaming position by a vertically movable foaming jig. Similarly, in Zastrow U.S. Pat. No. 4,691,906 a plurality of cores are carried on a common rotatable drum and rotated into position. However, in this patent the selected core is lowered by a core carrier into the foaming position.
These devices suffer form numerous shortcomings. Amongst them, such rotating core-holding devices preclude an operator from working on one core concurrent with the interchangeable utilization of two or more other cores. That is, each of the cores are provided with tooling panels mounted thereon which tooling panels are interchangeable upon their respective cores to allow variations in the size and shape of a core by merely interchanging the tooling panels thereof. It is desirable to be able to perform a tooling panel changeover on a given core which is not in use while a plurality of other cores continue to be manipulated into and out of their operative positions. This would allow production to continue throughout any tooling panel changeovers, thereby increasing production significantly. Since current devices provide each of the cores on a common rotating component, each and every one of the cores thereon necessarily rotate simultaneously, and no one core can be maintained in a stationary position, as is necessary to perform a tooling panel changeover, while the other cores are moved into and out of position. It is therefore desirable to provide a means for selectively interchanging two or more support cores while the plurality of temporarily unutilized cores remain stationary.
Additionally, downtime associated with any malfunctions of the rotary drive precludes utilization of any one of the cores, thereby resulting in the complete interruption of production until the rotary drive is repaired. It is desirable to provide an alternative means for selectively bringing the desired cores into their operative positions whereby separate actuators are employed for each of the respective cores. This would allow production to continue with the remaining cores despite a malfunction of any one of the actuators.
Separate and apart from the malfunction problem, the high cost and complexity of the rotary drives of the prior art present obstacles to their use in many instances. The cores or plugs of the type used in the refrigerator and freezer industry are large and heavy requiring complex and expensive bearing and support structures for the rotary head core supports of the prior art. These heads must also include drive means, indexing and locating means all of which are required to handle the heavy loads resulting from the mounting of multiple cores or plugs.
Similarly, with current apparatus, a malfunction in any one of the cores, such as a simple hang-up in the expansion and retraction of the retractile panels thereof, would result in the complete interruption of production while the malfunctioning core is removed or repaired. Significant increases in production may be realized by apparatus having separate actuators for each of the separate cores whereby the malfunctioning core can be maintained in a stationary position and repaired thereat, concurrent with the remaining cores being selectively moved into and out of their operative positions.
The ability to interchange cores allows for increased production rates, as it is significantly more rapid to change cores to accommodate different sizes of cabinets than to perform a tooling panel changeover. For instance, with current production methods, it typically takes approximately four minutes to inject insulation and allow it to cure sufficiently to allow removal of the support core therefrom. An additional 900 more cabinets can be produced per year per shift with a mere five second decrease in this interval between insulating of successive cabinets. Thus, it can be readily appreciated that the increased production which could be realized by apparatus so constructed is significant.
It is desirable to provide such an apparatus which is simple and economical both in its manufacture and operation. Also it is desirable to provide such apparatus which is capable of fully automated operation.